The medical treatment for such disease as cataract and the like is to replace an opaque crystalline lens with an artificial lens. In order to determine the vision before and after the replacement, there are demands for apparatus for measuring the pupillary accommodation ability (near reflex), and such apparatus is configured to measure the pupillary areas of the respective eyes on a single-eye basis. In the measurement, a subject is made to view a mark and the pupillary area in that state is measured.